Lecture 1: applied Neuroscience Flashcards
What are the Principle Roles of the Nervous System?
1) cognitive function
2) sensory motor function
3) motivation and emotion
4) regulatory function and homeostasis (autonomic NS)
What is the Functional Unit of the NS?
the Neuron
What does a Neuron consist of
soma, dendrites, axon, and presynaptic terminals
properties of myelin
1) able to repopulate
2) makes signals fast
3) increase with aerobic exercise
Synapses
- are a connection between the dendrite of one neuron to a cell body of another neuron
-grow quickly with motor practice - allow motion to become autonomic
Simple reflex
- Provide muscle with a quick stretch
- The body sends message to the motor system
- The motor system has a response
Types of Neurons
1) Motor Neuron
2) Sensory Neuron
3) Interneuron
Motor neuron properties
cell body, 1 long axon from the brain to the motor unit, motor unit/muscle.
Sensory neuron properties
receptor cell, axon, cell body within the axon, and dendrites
Interneuron properties
cell body, axon and synapses
The more dendrites means that
the more info that is able to be processed and more fine-tuned that signal can be
How many synapse does a spinal motor neuron usually have
800
Gray matter contains
cell body (soma ) and groups of cells (nuclei or ganglia)
white matter contains
Axons which contain myelin, they are groups of myelin that form pathways
In the brain where is the gray matter located?
on the outside
In the brain where is the white matter located
on the inside
In the spinal cord where is the gray matter located
on the inside
In the spinal cord where is the white matter located
on the outside
Fasciculi/ Fasciculus definition
White matter pathways or tracts (leminicus, tract, bundle within the brain)
what is the Commissure
the Fasciculi that connects the right and left hemispheres
Nucleus
a group of functionally related nerve cells
Ganglia
group of multiple nerve cells (Lentiform Nucleus or Basal Ganglia)
Column or Tracts
cerebral cortex and the spinal cord; group of nerve cell bodies and their axons that are all related in function
where is perception made
in the cortex
What does the Peripheral Nervous system Consist of
Autonomic nervous system, peripheral nerves, and cranial nerves (with the exception of CN 11)
The autonomic nervous system
parasympathetic and sympathetic
Parasympathetic
rest and digest: able to access by deep breathing
Sympathetic
Fight or flight
Cranial Nerves (with exception of 11)
originated from the brain stem and is used to test and see if there are problems with the brain
Posterior root ganglion (ganglia)
a group of nerve cell bodies lying in a peripheral nerve root (it forms a visual knot)
Posterior root
sensory neuron axons
what is afferent information
sensory info
what is efferent information
motor info
Root or Ramus
a peripheral structure with parallel axons
Anterior Horn
-Where motor info synapse
-Part of the PNS
-Polio makes inflammation at the anterior horn cells.
Anterior root is for what kind of neurons
motor
Spinal nerve is for what kind of neurons
sensory and motor
what is the pathway of afferent transmission to efferent information traveling
1) Afferent transmission
2) posterior root ganglion
3) Posterior root
4) dendrites
5) interneuron
6) Anterior horn
7) anterior root
8) spinal nerve
9) efferent transmission
What response does the body have when the parasympathetic nervous system is activated
Constrict pupils, stimulate saliva, slow heart beat, constrict airways, stimulate of the stomach, inhibit the release of glucose, stimulate gallbladder, stimulate the activity of intestines, contract bladder, promote erection of genitals
What response does the body have when the sympathetic nervous system is activated
Dilated pupils, inhibit salivation, increase heartbeat, relax airways, inhibit activity in the stomach, stimulate the release of the gallbladder, inhibit the activity of the intestines, secrete epinephrine and norepinephrine, relax the bladder, promote ejaculation and vaginal contraction.
Glial Cells in general
they are brain cells; provide critical support network for neurons. Involved in the pathogenesis of disease: alzheimers and MS
Types of Glia Cells
Astrocytes: “Star”
Oligodendrocytes
Ependymal Cells
Microglial Cells
Astrocytes
- Direct role in signaling
-Scavengers are clean up crew for the extracellular space
-nutrition for neurons
-Involved in memory - release neurotransmitters (glutamate)
- makes up 30-65% of glial cells
Oligodendrocytes
-provide myelin in CNS
- provide structural framework
Ependymal Cells
-produce cerebrospinal fluid waste clearance
- line ventricles and central canal
Microglial Cells (10% of brian cells)
- Function as the immune system in the NS
-Activated in NS disease, infection or injury - Dying neurons secrete proteins and attract microglia
What is Neuroinflammation mediated by
microglia and astrocytes
Abnormal glial activity is associated with
MS
Parkinsons
Head injury
Cells found the in Peripheral Nervous System
1) Satellite Cells
2) Schwann Cells
Satellite Cells
-Surround neuron cell bodies in the ganglia
-Regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in ganglia
Schwann Cells
- Surround the axons in the PNS
-Are responsible for myelination of peripheral axons
-Participate in repair process after injury
What is MS
when the immune system (bad microglia) attacks the oligodendrocytes
Multiple Sclerosis demyelination
-Causes a destruction of myelin
-Results in plaques (over time)
-Happens in the CNS
-Good microglia can regenerate oligodendrocyte
Alzheimers Disease
Good microglia : reduces inflammation
Bad microglia: increases inflammation
Gyrus (gyri)
Contains the cell bodies of the neurons dendrites and synapses
Sulcus (sulci)
The deeper the grooves the more cortical brain depth
The central sulcus
Divides the frontal lobe from the parietal lobe and the motor system from the sensory system.
The primary motor cortex
-In front of the central sulcus
-Is the area at stimulates or causes motor action
Premotor cortex and supplementary motor area
-This is where motor planning takes place
-In front of the primary motor cortex
Primary somatosensory cortex
-Right behind (posterior) the central sulcus
-Responsible for receiving and processing sensory information from across the body (such as touch, temperature, and pain)
Parietal association cortex
Sets up the sensory
Sylvian/ lateral fissure
Divides the temporal lobe
Corpus callosum
-In the center of the brain and connects the 2 hemispheres
-White matter
Betz Cells
A type of pyramidal neuron
Multipolar neuron
Connect to their axon and descend to the spinal cord via the corticospinal tract, where they synapse with the anterior horn cells.
Over 50% of betz cells originate from the primary motor cortex
The mortor cortex is divided into six layers of laminal
Betz and pyramidal cells originate mostly from laminal 5 and 6 in gray matter
The Lateral Corticospinal Tract
-Crossing at the cervicomedullary junction (where deputation happens)
-Movement in the left side comes from the right side of the brain
The Anterior Corticospinal Tract
-Does not cross over and stays unilaterally.
- Allows the UE to lift objects and support the head
-Provides stabilization, posture and power
Upper motor neuron
-One long axon from the primary motor cortex to anterior horn cell
-Involves the brain and spinal cord or CNS
-Trauma, diseases or infections occurring in these structures are identifies as “upper motor neuron” lesions
Lower Motor Neurons
-Involves the AHC (anterior horn cell) and the peripheral nerves
-Injuries , diseases or infection occurring in these areas are identifies as lower motor neuron lesions
Motor neuron Pathway
Pass through the internal capsule in the cerebral penduncles to the anterior pons, the pyramids of the medulla, and the lateral spinal cord to produce movements and fine movements
what percentage of neurons from the lateral corticospinal tract travel ipsilaterally
10%
Steps of motor system activation
-Posterior cortex provides sensory info to the frontal cortex
-Prefrontal cortex plans movements
-Premotor cortex organizes movement sequences
-Motor cortex produces movement.
Steps in Voluntary Motor activation
-Decision made in the frontal lobe (PF)
-Motor planning areas and command centers (pre motor and vision)
-Motor tract deliver signals to alpha motor neuron (AMNs and M1)
-Alpha motor neuron (AMN) transmit signals directly to skeletal muscles, eliciting contraction of skeletal muscle fibers
-Correction/ feedback of motor activity in cerebellum and the sensory cortex, regulate the activity in descending motor tracts.
what are the ways to increase muscle force
1) increased firing speed
2) increase the number of motor neurons
Motor pools
groups of muscles that cluster into discrete neurons, anterior horn cells (AHCs) with a common target muscle cell
- located in the spinal cord
- more pools = more strength
what is an S type alpha motor neuron
slow, small, and high excitability (first recruited)
what is an FR type alpha motor neuron
Fatigue Resistant, Big, and average excitability (2nd recruited)
what is FF type alpha motor neuron
Fast Fatigable, very big, low exitability (3rd recruited)
what type of motor unit produces high force and high power?
type 2
what type of motor unit produce slow force and lower power?
type 1
